Patient support pad

ABSTRACT

A support pad, including a first cushion layer, a second cushion layer, and a sensing device, is provided. The sensing device is positioned between the first and second cushion layers. The sensing device includes a plurality of sensing elements and a substrate. The substrate includes a plurality of tab portions and a plurality of expandable portions. The sensing elements are respectively mounted to the tab portions. The expandable portions are moveable between contracted and expanded positions in response to pressure applied thereto.

FIELD OF INVENTION

The present invention relates generally to the field of patient supportdevices, and, more particularly, a support pad having embeddedelectronic components.

BACKGROUND OF INVENTION

A support pad is typically used to support a patient undergoing asurgical procedure. The patient positioned on the support pad applies aload to the support pad. At least a portion of the load is resisted bythe support pad. The resistance of the support pad serves to create aninterface pressure at the surface of the support pad on which thepatient is positioned. The interface pressure is applied to thepatient's tissues contacting the surface of the support pad. Pressureulcers are more likely to develop in tissues that have been exposed tolong periods of elevated interface pressure.

An amount of interface pressure applied to the tissues is generallyrelated to respective loads applied to the support pad and an ability ofthe support pad to redistribute loads over the surface of the supportpad. For example, a rigid support pad may be less likely to effectivelyredistribute loads therein than a soft support pad due to an inabilityof a surface of the rigid support pad to envelop the loads. This is atleast partially due to the tendency of rigid surfaces to resist anapplication of force thereto. Thus, a greater peak of interface pressuremay be applied to the tissues by the rigid pad than the soft pad.

Pressure sensing devices or other electronic components embedded in asupport pad (e.g., temperature sensing, heating or excitation devices)are commonly positioned adjacent to an outer surface of the support pad.However, these electronic components are generally semi-rigid, therebyleading to increases in interface pressure and reduced loadredistribution through the support pad.

The present invention provides a support pad with embedded electroniccomponents that overcomes these and other drawbacks of the prior art.

SUMMARY OF INVENTION

In accordance with the present invention, there is provided a supportpad. The support pad includes a first cushion layer, a second cushionlayer, and a sensing device. The sensing device is positioned betweenthe first and second cushion layers. The sensing device includes aplurality of sensing elements and a substrate. The substrate includes aplurality of tab portions and a plurality of expandable portions. Thesensing elements are respectively mounted to the tab portions. Theexpandable portions are moveable between contracted and expandedpositions in response to pressure applied thereto.

In accordance with another embodiment of the present invention, there isprovided a support pad. The support pad includes a first cushion layer,a second cushion layer, and an electronic device. The electronic deviceis positioned between the first and second cushion layers. Theelectronic device includes a plurality of electronic elements and asubstrate. The substrate includes a plurality of tab portions and aplurality of expandable portions. The electronic elements arerespectively mounted to the tab portions. The expandable portions aremoveable between contracted and expanded positions in response topressure applied thereto.

In accordance with a further embodiment of the present invention, thereis provided a support pad assembly. The support pad assembly includes afirst support pad. The first support pad includes a first cushion layer,a second cushion layer, and a sensing device. The sensing device ispositioned between the first and second cushion layers. The sensingdevice includes a plurality of sensing elements and a substrate. Thesubstrate includes a plurality of tab portions and a plurality ofexpandable portions. The sensing elements are respectively mounted tothe tab portions. The expandable portions are moveable betweencontracted and expanded positions in response to pressure appliedthereto.

An advantage of the present invention is the provision of a support padthat enables improved redistribution of loads applied to the supportpad.

Another advantage of the present invention is the provision of a supportpad including a sensing device that enables accurate sensing ofinterface pressure for both acute and distributed loads applied totissues of a patient at a surface of the support pad.

An additional advantage of the present invention is the provision of asupport pad including a sensing device designed to reduce interfacepressure generated at a surface of the support pad without causing anappreciable difference to interface pressure.

A further advantage of the present invention is the provision of asupport pad including electronic components located on a substrate thatis flexible, strong, and compatible with printed electronic devices.

These and other advantages will become apparent from the followingdescription of a preferred embodiment taken together with theaccompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take physical form in certain parts and arrangement ofparts, a preferred embodiment of which will be described in detail inthe specification and illustrated in the accompanying drawings whichform a part hereof, and wherein:

FIG. 1 is a perspective view illustrating a support pad assemblyaccording to an embodiment of the present invention, wherein the supportpad assembly is positioned on an example surgical table;

FIG. 2 is a cross-sectional view of a support pad taken along lines 3-3of FIG. 1 according to an embodiment of the present invention;

FIG. 3 is a top view of a sensing device of the support pad shown inFIG. 2 according to an embodiment of the present invention;

FIG. 4 is an enlarged view of a portion of the sensing device shown inFIG. 3 according to an embodiment of the present invention;

FIG. 5 is a schematic view of a monitoring system according to anembodiment of the present invention;

FIG. 6 is a cross-sectional side view illustrating an example of asupport pad according to an embodiment of the present invention to whicha distributed load is applied; and

FIG. 7 is a cross-sectional side view illustrating an example of asupport pad according to an embodiment of the present invention to whichan acute load is provided.

DETAILED DESCRIPTION OF INVENTION

The present invention will now be described with reference to a supportpad that includes a pressure sensing device. However, it will beappreciated that the support pad of the present invention may alsoinclude other electronic devices, including, but not limited to,temperature sensing, strain sensing, moisture sensing, ultravioletenergy sensing, heating, and excitation devices.

Referring now to the drawings wherein the showings are for the purposesof illustrating embodiments of the invention only and not for thepurposes of limiting same, FIG. 1 shows a support pad assembly 6according to an embodiment of the present invention. Support padassembly 6 is positioned on a support surface 4 of a surgical table 2 tosupport and cushion a patient that is situated thereon.

In the illustrated embodiment, support pad assembly 6 is generallycomprised of support pads 8, 10, and 12 for respectively supporting andcushioning a head, a torso, and a leg/foot region of a patient.

Support pad assembly 6 is generally comprised of one or more supportpads according to patient positioning needs. While support pads 8, 10,and 12 are illustrated as being positioned on support surface 4 ofsurgical table 2, it will be readily appreciated that support pads 8,10, and 12 may be used to support and cushion a patient on any suitablesupport surface known in the art. For example, support pads 8, 10, and12 may be used in connection with support surfaces of a hospital bed, anexamination table, a mattress, a foam pad, a gurney, and the like. Inaddition, support pads 8, 10, and 12 may be configured to accommodatevarious patient positions, including, but not limited to, supine, prone,lithotomy, lateral, trendelenberg, reverse trendelenberg, beach chair,and seated positions. Further, in an alternative embodiment, support padassembly 6 is a single support pad sized to cover an entire area ofsupport surface 4.

FIG. 2 shows a cross-sectional view of support pad 10 taken along lines3-3 of FIG. 1 according to an embodiment of the present invention.Support pad 10 is generally comprised of a cover 24 and a layer assembly26, both of which are radiolucent. Cover 24 surrounds and houses layerassembly 26, and also defines top and bottom surfaces 20 and 22 ofsupport pad 10. A patient is positioned on top surface 20. Bottomsurface 22 is positioned on a support surface, such as support surface4. Cover 24 may be comprised of a soft and pliable polymer material thatstretches in response to applied pressure, such as, but not limited to,vinyl-based materials. An example thickness of support pad 10 is in arange of about 1.0 inch to about 5.0 inches, but is not limited thereto.

In the illustrated embodiment, layer assembly 26 is generally comprisedof, from a bottom to a top thereof, a lower cushion layer 40, acontroller unit 38, a middle cushion layer 34, a sensing device 32, andan upper cushion layer 28.

Upper cushion layer 28 is located adjacent to top surface 20 of supportpad 10. Upper cushion layer 28 provides tactile isolation of sensingdevice 32 from top surface 20 of support pad 10. In the illustratedembodiment, upper cushion layer 28 is comprised of a foam materialhaving a thickness in a range of about 0.125 inches to about 0.75 inchesand a density in a range of about 2.8 lbs/ft³ to about 5.0 lbs/ft³.Suitable types of foam material for upper cushion layer 28 include, butare not limited to, soft core memory foam, visco-elastic foam,gel-infused foam, slow-recovery foam, latex foam, or other flexiblepolyurethane foam material. Other suitable materials for upper cushionlayer 28 include, but are not limited to, cotton, latex, and polyester.

FIG. 3 shows a top view of sensing device 32 of support pad 10 shown inFIG. 2 according to an embodiment of the present invention. FIG. 4 showsan enlarged view of a portion of sensing device 32 shown in FIG. 3according to an embodiment of the present invention.

Sensing device 32 is positioned between upper and middle cushion layers28 and 34. A bottom surface 30 of upper cushion layer 28 and a topsurface 36 of middle cushion layer 34 are in contact with sensing device32. Sensing device 32 is generally comprised of a substrate 50, aplurality of sensing elements 52, at least one communication interface54, and a plurality of conductive trace lines 99.

Sensing elements 52 are configured to sense pressure applied by a loadonto cover 24 and transmitted through cover 24 and upper cushion layer28. In the illustrated embodiment, each sensing element 52 is aload-sensitive resistor sensing cell, or a sensel, but is not limitedthereto.

As best seen in FIG. 4, substrate 50 is generally comprised of aplurality of row and column sections 97 and 100 on which conductivetrace lines 99 are respectively formed, a plurality of tab portions 98on which sensing elements 52 are respectively located, and openings 103defined by row sections 97, column sections 100, and tab portions 98.Conductive trace lines 99 electrically connect sensing elements 52 withcommunication interfaces 54 located at the edge of sensing device 32.

Each column section 100 includes at least one expandable portion 101that is biased in a contracted position. Each expandable portion 101 ismoveable between contracted and expanded positions and configured toexpand in response to a load applied to upper cushion layer 28. Sectionsof conductive trace lines 99 that are respectively formed on expandableportions 101 expand and contract according to the expansion andcontraction of expandable portions 101. Further, each tab portion 98 hasa fixed end 107 attached to a row section 97 and a free end 105extending from the row section 97 into a corresponding opening 103. Eachtab portion 98 is free to move and flex within the respective openings103.

In the illustrated embodiment, sensing device 32 is arranged as a layerof layer assembly 26. However, it will be appreciated that otherarrangements of the above-referenced elements of sensing device 32 andsubstrate 50 may be implemented and will be apparent to those ofordinary skill in the art.

Further, in the illustrated embodiment, substrate 50 serves to provide amatrix of sensing elements 52. However, the structure of substrate 50and arrangements of sensing elements 52 located on substrate 50 are notlimited thereto. Additionally, it is conceivable for row sections 97 toinclude expandable portions 101 in place of or in addition to expandableportions 101 of column sections 100. Moreover, in the illustratedembodiment, substrate 50 is made of a flexible polymer sheet. Othersuitable materials for substrate 50 include, but are not limited to,polyethylene terephthalate (PET), polyimide, and thermoplasticpolyurethane.

Referring again to FIG. 2, middle cushion layer 34 is positioned betweensensing device 32 and controller unit 38. In the illustrated embodiment,middle cushion layer 34 is a foam layer having a thickness in a range ofabout 1.0 inch to about 4.0 inches and a density in a range of about 2.5lbs/ft³ to about 4.0 lbs/ft³. It will be appreciated that middle cushionlayer 34 may be split into multiple cushion layers constructed of thesame or different materials. For example, middle cushion layer 34 may beformed of cushion materials as described above in connection with uppercushion layer 28, such as, but not limited to, soft core memory foam,gel-infused foam, and polyurethane foam.

Controller unit 38 is positioned between middle cushion layer 34 andlower cushion layer 40. In the illustrated embodiment, controller unit38 is arranged as a layer of layer assembly 26. However, the arrangementof controller unit 38 is not limited thereto. Further, controller unit38 may be embedded in cushion material to protect controller unit 38from damage. In addition, it is contemplated that controller unit 38 maybe located inside a housing unit.

The cushion material embedding controller unit 38 may include, but isnot limited to, closed cell foam, rubber, and those materials describedabove in connection with upper and middle cushion layers 28 and 34. Forexample, such cushion materials of controller unit 38 may take the formof a foam material having a thickness in a range of about 0.25 inches toabout 0.5 inches and a density in the range of about 4.0 lbs/ft³ toabout 20.0 lbs/ft³.

Lower cushion layer 40 is located adjacent to bottom surface 22 ofsupport pad 10. In the illustrated embodiment, lower cushion layer 40 iscomprised of a foam material having a thickness in a range of about0.125 inches to about 0.375 inches and a density in a range of about 1.5lbs/ft³ to about 2.5 lbs/ft³. The foam material may take the form of aclosed cell rubber material. However, lower cushion layer 40 mayalternatively be formed of cushion materials as described above inconnection with upper cushion layer 28.

It is noted that respective layer assemblies (not shown) of support pads8 and 12 generally correspond with layer assembly 26 of support pad 10.Moreover, respective sensing devices 42 and 44 (see FIG. 5) of supportpads 8 and 12 may be generally comprised of the same basic components assensing device 32 of support pad 10. In addition, it will be appreciatedthat the inventive concepts described in terms of support pad 10 applyequally to support pads 8 and 12. Therefore, detailed descriptions ofsupport pads 8 and 12 are omitted.

However, in the illustrated embodiment, support pads 8 and 12 havedifferent dimensions than support pad 10. In this respect, support pads8 and 12 are respectively dimensioned to support head and leg/footregions of the patient.

FIG. 5 shows a monitoring system 120 according to an embodiment of thepresent invention. Monitoring system 120 is generally comprised of adata acquisition system 132, at least one wireless communication module130, respective sensing devices 42, 32, and 44 of support pads 8, 10,and 12, and respective controller units 122, 38, and 126 of support pads8, 10, and 12.

In the illustrated embodiment, controller units 122, 38, and 126 arerespectively electrically connected to sensing devices 42, 32, and 44via respective communication interfaces 56, 54, and 58. Controller units122, 38, and 126 receive respective signals from sensing devices 42, 32,and 44 indicative of pressure data sensed by sensing elements 52. In theillustrated embodiment, controller units 122 and 126 are furtherconfigured to relay respective pressure data received from sensingdevices 42 and 44 to controller unit 38. The connections betweencontroller units 122, 38, and 126 may be wired or wireless connections.

In the illustrated embodiment, controller unit 38 aggregates thepressure data originally acquired by sensing devices 42, 32, and 44 andcommunicates with data acquisition system 132 via wireless communicationmodule 130. Controller unit 38 sends the aggregated data to dataacquisition system 132 for storage and display of the aggregated data.It will be appreciated that wireless communication module 130 useswireless communication protocols well known to those skilled in the art.

In the illustrated embodiment, controller unit 38 serves as a mastercontroller, while controller units 122 and 126 serve as slavecontrollers. In this respect, controller unit 38 communicates withcontroller units 122 and 126, and with data acquisition system 132.However, the embodiments described herein are not limited thereto.Further, it will also be appreciated that other suitable arrangementsfor controller units 122, 38, and 126 may be implemented and will beapparent to those of ordinary skill in the art. For example, controllers122 and 126 may send data collected from respective sensing devices 42and 44 directly to data acquisition system 132 via wired or wirelessmeans.

In addition, wireless communication module 130, respective sensingdevices 42, 32, and 44 of support pads 8, 10, and 12, and respectivecontroller units 122, 38, and 126 of support pads 8, 10, and 12 mayreceive power through surgical table 2 or any number of means known toone having ordinary skill in the art.

In the illustrated embodiment, data acquisition system 132 is generallycomprised of a processing unit 134, an input unit 136, a data storageunit 138, and a display unit 140. Processing unit 134 receives theaggregated data from controller unit 38 and processes the data forstorage in data storage unit 138 and/or for display by display unit 140.Input unit 136 is used to request data from data storage unit 138 to beretrieved for processing by processing unit 134 and display by displayunit 140.

Manifestations of data acquisition system 132 may be implemented andwill be apparent to those of ordinary skill in the art. For example, itwill be readily appreciated that data acquisition system 132 may becontained within a personal computing device or distributed over aplurality of computing devices in multiple locations.

Data acquisition system 132 may advantageously employ any combination ofcomputing devices, user inputs, displays, notification devices, storageservers, and networking components known to one having ordinary skill inthe art. Input unit 136 may include, but is not limited to, a keyboard,a mouse controller, and a touch-screen. Display unit 140 may include,but is not limited to, a video display, a projector, and a printer.Devices corresponding with input unit 136 and display unit 140 are wellknown to the ordinary skilled artisan. It will be further appreciatedthat the processed data may be manifested in the form of pressure maps,pressure ulcer risk maps, graphs, or statistics, or any combinationthereof.

FIG. 6 shows a cross-sectional side view illustrating an example ofsupport pad 10 according to an embodiment of the present invention towhich a distributed load is applied. Patient 150 is illustrated in FIG.6 as applying a load to support pad 10 that is distributed, i.e.,generally uniform, across an area of support pad 10. It is noted that,for the purposes of this discussion, a distributed load may be caused byareas of patient 150 that are positioned flat on support pad 10. In theillustrated embodiment, an area of support pad 10 on which thedistributed load is applied generally corresponds to an area of loadredistribution within support pad 10.

In FIG. 6, the load applied by patient 150 is generally distributedacross top surface 20. It is assumed that cover 24 and upper cushionlayer 28 provide good load transmission, thereby resulting insubstantially direct transmission of the load through cover 24 and uppercushion layer 28 to sensing device 32. As a result, interface pressuresensed by sensing elements 52 is substantially equivalent to the loadapplied by patient 150 to support pad 10. Thus, pressure created byapplication of a distributed load of patient 150 to support pad 10 maybe accurately measured by sensing device 32 with minimal or no increasesin interface pressure.

FIG. 7 shows a cross-sectional side view illustrating an example ofsupport pad 10 according to an embodiment of the present invention towhich an acute load is provided. Patient 150 is illustrated in FIG. 7 asapplying a load to support pad 10 that is acute, i.e., generallyconcentrated in a small area of support pad 10. An acute load may becaused by bony prominences of patient 150 that are positioned on supportpad 10. Examples of bony prominences include, but are not limited to,areas of a pelvis of patient 150 or a heel of patient 150.

In FIG. 7, the illustrated bony prominence of patient 150 applies a loadto the top surface 20 of support pad 10. It is assumed that cover 24 andupper cushion layer 28 provide good load redistribution, therebyresulting in substantially indirect transmission of certain portions ofthe load through cover 24 and upper cushion layer 28 to sensing device32. Portions of the load applied by the bony prominence of patient 150create tangential shear forces. These tangential shear forces arecreated by the bony prominence around an area of top surface 20 at whichthe bony prominence is supported. The created tangential shear forcesare subsequently transmitted through cover 24 and upper cushion layer28.

Expandable portions 101, tab portions 98, and openings 103 allowsubstrate 50 to stretch in response to the concentrated load that isdirectly transmitted through cover 24 and upper cushion layer 28. Thus,substrate 50 has a reduced resistance to loads applied to top surface 20of support pad 10. The substrate 50 is further able to transmitcorresponding pressure from bottom surface 30 of upper cushion layer 28to top surface 36 of middle cushion layer 34. This allows bottom surface30 of upper cushion layer 28 and top surface 36 of middle cushion layer34 to conform to the stretched substrate 50, thereby reducing interfacepressure at top surface 20 of support pad 10. This also allows cover 24and upper cushion layer 28 to envelope the bony prominence of patient150.

As substrate 50 is stretched in accordance with the load applied by thebony prominence, the tangential shear forces created by the bonyprominence are transmitted through cover 24 and upper cushion layer 28in directions that are increasingly more normal and direct to sensingdevice 32. As a result, load exposure to corresponding areas of sensingdevice 32 is increased and sensing accuracy of sensing device 32 isimproved. Further, the resistance of substrate 50 to pressure isreduced. As a result, increases in the interface pressure at top surface20 of support pad 10 are minimized or avoided.

While the present invention is particularly applicable for sensingpressure from within support pad 10 and is described with referencethereto, it will be appreciated from a further reading of the presentdisclosure that the present invention finds advantageous application insensing other parameters from within support pad 10, such as, but notlimited to, temperature. For example, temperature sensing elements couldbe used in place of pressure sensing elements 52 to sense a temperatureof upper cushion layer 28.

Further, improved sensing accuracy of sensing device 32 may be achievedby other means in addition to the ability of substrate 50 to stretch.For example, sensing accuracy of sensing device 32 may additionally beimproved by minimizing the thickness of upper cushion layer 28, whichmay improve direct transmission of the loads to sensing device 32.

In addition, while the present invention is particularly applicable forsensing with sensing elements 52 positioned in support pad 10, it willbe appreciated from a further reading of the present disclosure that thepresent invention finds advantageous application in providing otherfunctions with electronic elements positioned in support pad 10. Thesefunctions may include, but are not limited to, heating with heatingelements positioned in support pad 10 and excitation with excitationelements positioned in support pad 10. For example, pressure sensingelements 52 may be replaced with heating elements to heat support pad10.

The foregoing description provides example embodiments of the presentinvention. It should be appreciated that these embodiments are describedfor purposes of illustration only, and that numerous alterations andmodifications may be practiced by those skilled in the art withoutdeparting from the spirit and scope of the invention. It is intendedthat all such modifications and alterations be included insofar as theycome within the scope of the invention as claimed or the equivalentsthereof.

Having described the invention, the following is claimed:
 1. A supportpad, comprising: a first cushion layer; a second cushion layer; and asensing device positioned between the first and second cushion layers,the sensing device comprising: a plurality of sensing elements; and asubstrate including: a plurality of row and column sections, each of thecolumn sections comprising one or more expandable portions biased in acontracted position, each expandable portion being configured to movebetween the contracted position and an expanded position in response topressure being applied thereto; a plurality of tab portions, saidsensing elements being respectively located on the tab portions; and aplurality of openings defined by the row sections, the column sections,and the tab portions, said tab portions being moveable within saidopenings, wherein each of said tab portions has a fixed end attached toone of the row sections and a free end extending from the one of the rowsections into a corresponding one of the openings.
 2. The support pad ofclaim 1, wherein the substrate further comprises a plurality ofconductive trace lines formed on the row and column sections forelectrically connecting the sensing elements.
 3. The support pad ofclaim 2, wherein the conductive trace lines are moveable in accordancewith the expandable portions.
 4. The support pad of claim 1, whereinsaid first cushion layer is comprised of a foam material.
 5. The supportpad of claim 4, wherein said foam material of said first cushion layerhas a density in a range of 2.8 lbs/ft³ to 5.0 lbs/ft³.
 6. The supportpad of claim 4, wherein said first cushion layer has a thickness in arange of 0.125 inches to 0.75 inches.
 7. The support pad of claim 1,wherein said second cushion layer is comprised of a foam material. 8.The support pad of claim 7, wherein said foam material of said secondcushion layer has a density in a range of 2.5 lbs/ft³ to 4.0 lbs/ft³. 9.The support pad of claim 7, wherein said second cushion layer has athickness in a range of 1.0 inch to 4.0 inches.
 10. The support pad ofclaim 1, wherein the pressure applied to the expandable portions iscreated by a load applied to the first cushion layer, wherein saidsensing elements are configured to sense the pressure applied to theexpandable portions, and wherein the load applied to the first cushionlayer is transmitted through the first cushion layer to the sensingelements.
 11. The support pad of claim 10, wherein the expandableportions expand in response to the load applied to the first cushionlayer.
 12. The support pad of claim 10, wherein the tab portions move inresponse to the load applied to the first cushion layer.
 13. The supportpad of claim 1, further comprising a cover that surrounds the firstcushion layer, the second cushion layer, and the sensing device.
 14. Thesupport pad of claim 1, further comprising a controller unit and a thirdcushion layer, said controller unit being located between the second andthird cushion layers.
 15. The support pad of claim 14, wherein thesensing elements are configured to sense the pressure applied to theexpandable portions, and wherein said controller unit is electricallyconnected to the sensing device to receive signals from the sensingdevice indicative of the pressure applied to the expandable portionsthat is sensed by the sensing elements.
 16. The support pad of claim 15,wherein said controller unit communicates with a data acquisition systemfor storing and displaying data acquired by the sensing device.
 17. Thesupport pad of claim 1, wherein the pressure applied to the expandableportions is applied by a bottom surface of the first cushion layer, andwherein the substrate is configured to transmit the pressure applied tothe expandable portions by the bottom surface of the first cushion layerto a top surface of the second cushion layer.
 18. The support pad ofclaim 1, wherein the row and column sections are disposed between thetab portions.
 19. A support pad assembly, comprising: a first supportpad, comprising: a first cushion layer; a second cushion layer; and asensing device positioned between the first and second cushion layers,the sensing device comprising: a plurality of sensing elements; and asubstrate including: a plurality of row and column sections, each of thecolumn sections comprising one or more expandable portions biased in acontracted position, each expandable portion being configured to movebetween the contracted position and an expanded position in response topressure being applied thereto; a plurality of tab portions, saidsensing elements being respectively located on the tab portions; and aplurality of openings defined by the row sections, the column sections,and the tab portions, said tab portions being moveable within saidopenings, wherein each of said tab portions has a fixed end attached toone of the row sections and a free end extending from the one of the rowsections into a corresponding one of the openings.
 20. The support padassembly of claim 19, further comprising a second support padelectrically connected to the first support pad, the second support padcomprising: a first cushion layer; a second cushion layer; and a sensingdevice positioned between the first and second cushion layers of thesecond support pad, the sensing device of the second support padcomprising: a plurality of sensing elements; and a substrate including:a plurality of row and column sections, each of the column sectionscomprising one or more expandable portions biased in a contractedposition, each expandable portion of the second support pad beingconfigured to move between the contracted position and an expandedposition in response to the pressure applied to the expandable portionsof the first support pad; a plurality of tab portions, said sensingelements of the second support pad being respectively located on the tabportions of the second support pad; and a plurality of openings definedby the row sections of the second support pad, the column sections ofthe second support pad, and the tab portions of the second support pad,said tab portions of the second support pad being moveable within saidopenings of the second support pad, wherein each of said tab portions ofsaid second support pad has a fixed end attached to one of the rowsections of the second support pad and a free end extending from the oneof the row sections of the second support pad into a corresponding oneof the openings of the second support pad.